The invention relates to a linear vibratory conveyor that includes a utility weight and a counterweight that can be vibratingly moved in opposing directions via a drive unit, the drive unit being coupled to the utility weight and to the counterweight and being arranged in a receiving chamber beneath the utility weight.
Such linear vibratory conveyors transport small and very small articles or components that are to be supplied to a working or assembly machine where they are to be processed or installed. The linear vibratory conveyor linearly transports the parts, which are advanced via micro-jumps due to the vibrations generated in the transport rail and along which rail the components are moved. The structure of such a linear vibratory conveyor basically includes a base plate via which the conveyer can be attached to a machine table or the like, and a counterweight and a utility weight, which are both coupled via a drive unit and using the latter can be caused to vibrate in opposition to one another, which is why the utility weight and the counterweight are coupled, vibrationally movable, to the base plate via corresponding spring elements, usually leaf spring packets. In order to facilitate compact construction beneath the utility weight, which includes the transport rails, the drive unit is arranged in a receiving chamber disposed there between utility weight and base plate.
Generally an electromagnetic drive, that is, an electromagnet, is used for the drive unit. The magnet core is connected to the winding that surrounds it and to the counterweight, while the magnet armature is connected to the utility weight. By appropriately controlling the winding with a suitable alternating voltage, an alternating magnetic field that acts on the armature is created and produces the vibratory movement in a manner known per se.
However, also known is using a drive unit that includes a piezo-electric actuator that is arranged on a leaf spring of the conveyor that can be bent using the actuator. When an alternating voltage is applied, such a piezo-electric actuator undergoes a voltage-induced reversible change in shape that is transmitted to the spring element for generating vibration. Compared to using an electromagnet, vibrations with significantly higher frequencies can be generated with such a piezo-electric actuator. Thus for both drive units there are special application areas that require or justify the corresponding use of either the one or the other drive unit.
It is disadvantageous that the structural design of known linear vibratory conveyors that are provided for using electromagnets is different from that when using a piezo-electric actuator, especially with respect to coupling the drive unit to the utility weight and to the counterweight, so that different structural forms result as a function of drive unit. This consequently requires that different components be produced and maintained in inventory.